Bar code reading systems for reading preprinted bar codes are well known and are used in many diverse applications, such as, for example, shipping, manufacturing, and retail checkout applications. The bar code reading systems are generally arranged to read one or more of the industry standard bar code formats, such as, for example, Code 39, Interleaved 2 of 5, Discrete 2 of 5, Code 128, Code 93, Codabar, UPC, etc. A bar code reading system reads and decodes the bar codes and forms a digital representation of the data which can then be displayed and/or provided to a host computer for subsequent processing.
The industry standard bar codes are generally encoded and pre-printed on an item (i.e., pre-printed bar code on a grocery item) or are encoded and machine printed on an adhesive label using a printer. Symbol Technologies Inc. portable printer Model No. PS1000 is illustrative of a printer for encoding and printing industry standard bar code labels.
Hand-mark sense system are also known which read hand-mark sense information from a document. A common example of a document using hand-mark sense information is a multiple choice examination, where the user darkens predetermined areas on the document corresponding to the desired answer to a question. A hand-mark sense reader then detects the various darkened areas on the document, and based on the relative position of the darkened areas on the document, information describing the hand-mark sense information is formed. To determine the relative position of the darkened areas on the document the hand-mark sense reader must accurately feed or position the document relative to the reader. Accordingly, variations in the size and shape of the document are limited. Finally, it is noted that a hand-mark sense reader is entirely different than a bar code reader, is not capable of reading bar codes, and generally costs more to produce than bar code readers.
There are many applications in which it is desired to combine both pre-printed bar code symbols with user enterable data (hand-mark sense information) on the same document. U.S. Pat. No. 4,877,948 describes a system for reading a document which contains both pre-printed bar codes and hand-mark sense information. In the U.S. Pat. No. 4,877,948, fixed information, which can not be modified by the user, is encoded and pre-printed as bar codes. The hand-mark sense information is entered by the user in an area on the document different from where the bar codes are printed. A reading device comprising in combination a bar code scanning device and a hand-mark sense reading device is arranged to read the bar code and the hand-mark sense information, respectively, and to form information descriptive thereof. However, as can be appreciated, the manufactured cost for the combination reader is inherently greater than the manufactured cost of just the bar code scanning device.
U.S. Pat. No. 4,728,784 discloses a method and system for reading hand modified bar codes. The reading device of the U.S. Pat. No. 4,728,784 is arranged to read a unique preprinted bar code having a portion thereof hand-modified by a user. The hand-modified bar code is then scanned using a bar code reader and decoded by a unique decoding algorithm which detects which portion of the unique preprinted bar code has been hand-modified. Based upon the position of the hand-mark within the pre-printed bar code, a predetermined character is output by the reading device. However, it is noted that the encoding format of the data is entirely different than the industry standard formats. Accordingly, bar code readers that are arranged to decode bar codes encoded in the industry standard formats can not be used for decoding the bar codes described in the U.S. Pat. No. 4,728,784.